Catheter having exchangeable balloon

ABSTRACT

An intravascular balloon catheter comprises a tubular catheter body having a balloon structure removably mounted over the catheter body. The catheter body has a guidewire lumen, and the catheter body may be left in place within a patient&#39;s vasculature while the balloon structure is withdrawn and optionally a second balloon structure introduced over the catheter body. The catheter and methods of the present invention are particularly suitable for performing angioplasty and subsequent procedures, such as stent placement, which are best performed using successive interventional balloon structures.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part patent application ofand claims the benefit of priority from U.S. patent application Ser. No.09/585,943 filed Jun. 2, 2000, now U.S. Pat. No. 6,569,180 the fulldisclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical devices and methods.More particularly, the present invention relates to a balloon catheterhaving an exchangeable balloon structure.

Percutaneous transluminal angioplasty procedures have become a therapyof choice for treating stenosed regions in the patient's vasculature,particularly the coronary vasculature. Recently, the use of suchangioplasty procedures has often been combined with stent placementand/or radiation treatment to inhibit restenosis and hyperplasiafollowing angioplasty. When performing such multiple, sequentialtreatments, it is usually necessary to “exchange” catheters which areused to perform each of the procedures. That is, the initial angioplastytreatment will be performed using a balloon angioplasty catheter. Afterthe angioplasty is completed, a second catheter carrying a stent orother vascular prosthesis must then be introduced to the treatment site.Introduction of the second catheter involves first removing the balloonangioplasty catheter and then placing the second catheter in thetreatment region. Optionally, a third catheter may then be exchanged forthe second in order to perform radiation or other treatments in order toinhibit hyperplasia.

In performing such multiple, sequential treatments, most physiciansprefer to leave a “guidewire” in place to the treatment location. Aguidewire is a small diameter, highly flexible wire that can be steeredto the target location through the vasculature and which then acts as aguide path for introducing and positioning the balloon angioplasty andother interventional catheters.

In the early days, balloon angioplasty catheters were designed to beintroduced into the vasculature in an “over-the-wire” manner. That is,the catheters were designed to have passages, commonly referred to asguidewire lumens, which extended the entire distance from the distal endof the catheter to the proximal end of the catheter. The catheter couldthen be loaded over a proximal end of a guidewire which was already inplace in the patient and then advanced over the guidewire until a distalend of the catheter reached the target site. While functional, the needto maintain control of the guidewire while the interventional catheterwas being introduced meant that the guidewire had to have an excesslength outside of the patient which was greater than the length of thecatheter being introduced. If the length were any shorter, the treatingphysician would not be able to hold on to the guidewire as the catheterwas being introduced. Although necessary for catheter introduction, theexcess guidewire length (optionally in the form of a detachableextension) was very difficult to manage during other parts of thetreatment.

To overcome the difficulties associated with very long guidewires “rapidexchange” or “monorail” balloon angioplasty catheters were developed. Anumber of specific designs have been developed over the years, and therapid exchange catheters generally have a shortened guidewire lumenwhich extends from a distal tip of the catheter to an exit port locatedcloser to the distal end of the catheter than to the proximal end. Byreducing the length of the guidewire lumen, the need for a guidewirehaving excess length outside of the patient is also reduced.

The use of rapid exchange catheters has become wide spread, and theyhave proven to be particularly valuable for use as stent deliverycatheters. Stent delivery catheters are normally used after an initialangioplasty treatment. In such cases, the angioplasty catheter will beremoved and exchanged for the stent delivery catheter. Use of anangioplasty catheter having a rapid exchange design facilitates removalof the angioplasty catheter over short guidewires. Similarly, use of thestent delivery catheter having a rapid exchange design facilitatesintroduction of the catheter over the guidewire which remains in placein the patient.

Despite their widespread acceptance, rapid exchange catheters sufferfrom a number of limitations. In particular, the shortened guidewirelumens reduce the “pushability” of the rapid exchange catheters. The useof full length guidewire lumens as provided by the over-the-wire designsresults in an overall increase in the column strength of the catheterbeing introduced. That is, the catheter derives column strength not onlyfrom the catheter body itself, but also from the guidewire which is inplace in the guidewire lumen over the entire length of the catheter,allowing better access across tight lesions. Additionally, presence ofthe guidewire in a full length guidewire lumen lessens the risk of thecatheter body kinking or collapsing in tortuous regions of thevasculature. Kinking can be a particular problem at the point where theguidewire exits a catheter body in a rapid exchange design.

The second problem associated with the use of rapid exchange cathetersis the inability to exchange the guidewire. Guidewire exchange inover-the-wire catheters is quite simple since the guidewire lumenextends the fall length of the catheter body. In rapid exchangecatheters, in contrast, there is no guidewire lumen in the proximalportions of the angioplasty catheter. It is therefore difficult toreintroduce a guidewire into the shortened guidewire lumen of the rapidexchange catheter.

For these reasons, it would be desirable to provide improved apparatus,methods, and kits which permit the exchange of catheters and cathetercomponents over shortened guidewires. Particularly, it would bedesirable to provide improved balloon angioplasty and other catheterswhich can be introduced to the vasculature in the manner of anover-the-wire catheter, but which allow removal of the catheter over ashortened guidewire and/or which permits exchange of catheter componentsover the catheter body which remains in place over the guidewire. Itwould be further desirable to provide balloon catheters and methods fortheir use which permit exchange of balloon structures over the catheterbody while the catheter body remains in place in the vasculature over aguidewire and where the replacement balloon structure may optionallycarry a stent. At least some of these objectives will be met by theinvention described in claims herein after.

2. Description of the Background Art

Rapid exchange catheters having guidewire exchange devices are describedin U.S. Pat. Nos. 5,281,203; 5,571,094; and 5,919,175. Sleeves forpositioning stents, drug infusion tubes, imaging transducers, and otherinterventional devices over balloon angioplasty catheters are describedin U.S. Pat. No. 5,776,191; 5,810,869; and PCT Publication W097/07756.Rapid exchange and related catheters are described in U.S. Pat. Nos.6,056,722; 6,007,517; 5,980,4861; 5,947,927; 5,921,971; 5,919,164;5,891,056; 5,846,246; 5,833,659; 5,830,227; 5,827,241; 5,807,355;5,814,061; 5,769,868; 5,855,685; 5,749,888; 5,738,667; 5,728,067;5,709,658; 5,685,312; 5,626,600; 5,620,417; 5,607,406; 5,554,118;5,545,134; 5,531,690; 5,501,227; 5,472,425; 5,468,225; 5,460,185;5,458,613; 5,451,223; 5,413,559; 5,395,335; 5,383,853; 5,364,376;5,350,395; 5,346,505; 5,336,184; 5,334,147; 5,328,472; 5,300,085;5,380,283; 5,263,963; 5,232,445; 5,195,978; 5,135,535; 5,061,273;5,040,548; 4,762,129; 4,988,356; 4,947,864; 4,748,982; and WO 99/13935.

SUMMARY OF THE INVENTION

The present invention provides improved intravascular balloon cathetersand methods for their use. The catheters are suitable for use for thetreatment of a variety of conditions within different locations of apatient's vasculature. In particular, the catheters can be used in thecoronary, peripheral, and cerebral regions of a patient's vasculaturefor virtually any treatment modality that relies on balloon expansion,particulaty angioplasty, stent placement, and the like.

Intravascular balloon catheters according to present invention comprisea catheter body having a proximal end, a distal end, and a guidewirelumen extending therebetween. Typically, the catheter body comprises atubular member having at least one lumen, i.e. single lumen tube ormultiple lumen tube. Usually, the guidewire lumen will extend the entiredistance from the proximal end to the distal end of the catheter,although in some instances the guidewire lumen could be shortened (inmanner of a conventional rapid exchange catheter), could be split tofacilitate removal of the guidewire, and/or could be provided with abreakaway feature which allows opening the guidewire lumen to facilitateguidewire removal. In all cases, the intravascular balloon catheters ofthe present invention will further comprise a balloon structure having apassage which is slidably receivable over the tubular catheter body.Thus, the balloon structure can be selectively introduced and removedover the tubular catheter body to permit exchange of the balloonstructure with another balloon structure (or in some cases a non-balloonstructure) either before or during performance of an intravascularinterventional procedure employing the balloon.

Usually, the balloon structure will comprise an inflatable component,e.g. a balloon, having an inflation tube extending proximally from theballoon when the balloon is disposed near the distal end of the tubularcatheter body. Conveniently, the inflation tube can also be used tomanipulate the balloon structure. That is, the balloon structure can beadvanced and withdrawn over the tubular catheter body by pushing andpulling on a proximal end of the inflation tube while the tubularcatheter body remains in place. In such cases, the inflation tube willhave sufficient column strength to advance and retract the balloonstructure over the tubular catheter body. Usually, it will be in theform of a hypotube, but other structures would also be possible.Alternatively, a separate manipulation shaft could be attached to theballoon structure with a separate inflation structure, either attacheddirectly to the balloon structure or optionally provided in the tubularcatheter body. In the later case, the tubular catheter body will includean inflation lumen and the balloon structure will include an inflationport which mates with the inflation lumen in order to permit inflationof the balloon through the tubular catheter body. A separatemanipulation shaft will then be provided on the balloon structureextending proximally from the balloon structure when the balloon isdisposed near the distal end of the tubular catheter body.

The inflatable structure, in an exemplary embodiment, will comprise aballoon attached to an inner sleeve. The inner sleeve has an axialpassage so that at least part of the inner sleeve is slidably receivableover the tubular catheter body. Usually, the inner sleeve will be longerthan the balloon, with the inner sleeve usually having a length in therange from 3 cm to 50 cm, usually from 4 cm to 40 cm, and typically from5 cm to 25 cm. The balloon or other inflatable structure (or in somecases other radially expansible structure) will be much shorter,typically being in the range from 1 cm to 5 cm, usually from 2 cm to 4cm. The inner sleeve may be formed from conventional catheter materials,typically being an extruded polymer tube.

When an inflation tube is attached to the balloon structure, the tubularcatheter body will preferably be free from structure which interfereswith introduction of the balloon structure over the proximal end of thetubular catheter body. Optionally, a hemomostatis structure may beprovided within the proximal end of the guidewire lumen, but thehemomostatis structure will not add to the profile of or otherwiseaffect the catheter body such that it would interfere with loading ofthe balloon structure. Alternatively, a removable hub could be provided,but upon removal of the hub, the proximal end of tubular catheter bodyshould be sufficiently free of protruding structure to permitintroduction of the balloon structure thereover. When the inflationlumen is provided within the tubular catheter body, it will be usuallybe necessary to provide a removable hub at the proximal end of thecatheter body to permit inflation of the balloon through a port on thehub.

The intravascular balloon catheters of the present invention willinclude at least a first balloon structure having the propertiesdescribed above. Usually, the first balloon structure will be preloadedover the tubular catheter body, and the assembly sterilized and packagedas a complete unit. Optionally, a second balloon structure having apassage which is slidably receivable over the tubular catheter body maybe also provided. The second balloon structure may be included as partof a single system together with the first balloon structure and tubularcatheter body, usually being packaged together in a sterile manner withthe other system components. Typically, the second balloon structurewill differ from the first in someway, such as the dimensions, includingdiameter, length, or both; shape; balloon material; ballooncharacteristics, such as compliance, flexibility, elasticity or thelike; or other feature. In a particular example, the second balloonstructure may carry a stent or other vascular prosthesis, where thefirst balloon structure is intended for performing angioplasty or othertherapeutic or diagnostic procedure, and the second balloon structure isintended to deliver a stent after the angioplasty treatment. Otherexamples include drug infusion balloons, radioactive delivery balloons,atherectomy, and the like. Of course, the intravascular ballooncatheters including only a single balloon structure may also be adaptedto carry a stent, drug infusion balloon, radioactive delivery balloon,or the like, as well. Alternatively or additionally, the intravascularballoon catheter of the present invention may further include a secondcatheter body having a passage which is slidably receivable over the“first” catheter body.

In some embodiments, the intravascular balloon catheters of the presentinvention may further comprise a deployable embolic capture element oneither the tubular catheter body or the first balloon structure. Thedeployable embolic capture element may comprise coils, wires, braids,mesh, and the like and take on a variety of shapes, i.e., funnel shape,parachute shape, etc. Preferably, the embolic capture element is formedfrom a nickel-titanium alloy (such as Nitinol™ alloy), spring stainlesssteel, or like materials and may additionally be coated or contained bya polymer material. The expandable embolic capture element allows forfiltering and/or suctioning of any emboli (which may potentially occludea body lumen) before, during, and/or after treatment with theintravascular balloon catheter. The embolic filter will typically havemicro size holes in the range of about 1 micron to 100 microns for theretrieval of emboli, wherein the embolic filter is released open andclosed, at least in part, by axial or radial movement of the inflatableballoon structure or the catheter body.

In another embodiment, the intravascular balloon catheters of thepresent invention may further comprise a second expandable balloon onthe catheter body distal to the first balloon structure. The secondballoon will have dimensions, characteristics, and be formed frommaterials similar to the first balloon structure, as described above.The second balloon itself may also carry an expandable vascularprosthesis that is balloon expandable. In some instances, the firstballoon structure may perform angioplasty or other therapeutic ordiagnostic procedures, while the second balloon may be intended todeliver a stent (balloon expandable) after the angioplasty treatment.Thus, such an embodiment advantageously allows for sequential treatmentsin a single catheter structure. In another embodiment, the intravascularballoon catheter of the present invention may comprise a self-expandingvascular prosthesis on the catheter body. The self-expanding prosthesismay be formed from steel, nickel titanium, shape memory alloy, cobalt,composite material, and the like. Typically, the self-expandingprosthesis will be deployed, at least in part, by axial or radialmovement of the first balloon structure or the catheter body.

In yet another embodiment, the intravascular balloon catheters of thepresent invention may have an axial groove over at least a portion ofthe inflation tube of the balloon structure so as to removably receive aportion of the catheter body. The groove is appropriately sized toaccommodate catheter body as disclosed herein, with a groove opening inthe range from 0.001 inches to 0.014 inches and an inner groove diameterin the range of about 0.0145 inches to 0.03 inches, preferably fromabout 0.016 inches to 0.02 inches. In particular, the axial groove ofthe inflation tube facilitates the introduction and withdrawal of thecatheter body.

Methods according to the present invention for balloon exchange over atubular catheter body comprise withdrawing a balloon structure coaxiallyover the tubular catheter body while the tubular catheter body remainsin place over a guidewire in a blood vessel. The balloon structure iswithdrawn proximally, usually so that it may be removed over a proximalend of the tubular end of the catheter body. After withdrawing a firstballoon structure, a second balloon structure is introduced over thetubular catheter body in distal direction while the tubular catheterbody remains in place over the guidewire. Typically, the second balloonstructure will be introduced over the proximal end of the tubularcatheter body. A particular advantage of the these methods is that thefirst balloon structure and tubular catheter body maybe introduced overa short guidewire (i.e. one that is only slightly longer than theangioplasty catheter itself e.g. 10 cm to 35 cm) in the manner of anover-the-wire angioplasty catheter. After the balloon catheter assemblyis in place, however, the first balloon structure may be withdrawn fromover the proximal end of the tubular catheter body and exchanged for asecond (subsequent) balloon structure. As the balloon structuresthemselves will be shorter than the catheter body, typically being from3 cm to 50 cm, they can be withdrawn without losing manual access to theproximal ends of the tubular catheter body and short guidewire.

In an exemplary protocol using the intravascular balloon catheters andmethods of the present invention, the balloon catheter comprising afirst balloon structure pre-loaded over a tubular catheter body is firstintroduced together with a guidewire to a target region in thevasculature in a conventional manner. Usually, a distal end of theguidewire, extends beyond the distal end of the tubular catheter body bya short distance as the balloon catheter assembly is being advanced. Inthat way, a short guidewire can be used where the guidewire is fullysupported in the guidewire lumen of the tubular catheter body, whichtypically runs the entire length of the catheter body.

After the first balloon structure has been positioned at the targetlocation within the vasculature, e.g. a stenosed region within thecoronary vasculature, the first balloon may be expanded to treat thetarget region, e.g. by opening the stenosed region. Thus, the firstballoon structure may act as angioplasty balloon, with the balloon beingsubstantially non-distensable at the relatively high inflation pressureis used, typically from 3 atmospheres to 20 atmospheres. Alternatively,the first balloon could be any other therapeutic or diagnostic-type ofballoon.

After the initial balloon treatment is completed, the balloon structuremay be withdrawn proximally from over the tubular catheter body. Thismay be accomplished by using the inflation tube when the balloonstructure includes such an inflation tube. Otherwise, withdrawal will betypically be accomplished using a shaft, such as a solid core wire orhypotube attached to the balloon structure and extending proximallytherefrom. The passage of the balloon structure, as described above,will usually be relatively short so that the balloon structure may bewithdrawn from over the proximal end of the tubular catheter body andguidewire, with the lengths of the tubular catheter body and guidewirebeing extended a small amount to allow manual access while the balloonstructure is being withdrawn thereover.

After the first balloon structure has been withdrawn, the second balloonstructure may be introduced over the proximal ends of both the guidewireand the tubular catheter body. Again, the length of the passage in thesecond balloon structure will typically be in the range from about 3 cmto 50 cm, so that manual access to both the tubular catheter body andguidewire will remain at all times. The second balloon structure may beadvanced using either an inflation tube or other manipulation shaftoverextending proximally from the balloon structure. The balloonstructure will then be advanced until it reaches a location near thedistal end of the tubular catheter body where it can be furtherpositioned within the treatment region. In the exemplary case, thesecond balloon structure will carry a balloon expandable stent or othervascular prosthesis, where the stent is implanted by expansion of thesecond balloon structure.

Optionally, further treatments can be provided, e.g. using a thirdcoaxial sleeve structure which could carry drugs, genes, radiation, orother therapeutic agents or modalities. The third coaxial structure may,but need not, also comprise an inflatable balloon. The third structureusually will be introduced in a manner analogous to the introduction ofthe second balloon structure, as just described. There, of course, couldbe fourth, fifth, and even more treatment steps performed bysuccessively introducing balloon, sleeve, and other structures over thetubular catheter body. Moreover, it will also be possible to introducetwo or more balloon structures over the tubular catheter body at thesame time.

After the patient treatment is completed, the intravasculature catheterstructure which remains over the guidewire will be withdrawn. In a firstoption, the catheter and guidewire can be withdrawn simultaneously wherethe catheter is never in the vasculature without the guidewire presentin the guidewire lumen. Alternatively, the balloon or other coaxialsleeve structure can be withdrawn from over the tubular catheter bodyprior to removing the tubular catheter body and guidewiresimultaneously. As a third option, the tubular catheter body could beprovided with an axial slit or break away portion to permit removal ofthe tubular catheter body from over the guidewire with the guidewireremaining in place. In that way the guidewire would remain in place forsubsequent use with other catheters or devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an intravascular catheter comprising a tubularcatheter body and a first balloon structure mounted over the catheterbody and constructed in accordance with the principles of the presentinvention.

FIG. 2 illustrates the intravascular balloon catheter of FIG. 1 shownwith the first balloon structure separated from the tubular catheterbody.

FIG. 3 is a cross-sectional view taken along line 3—3 of FIG. 2.

FIG. 3A is an alternative cross-sectional view taken along line 3—3 ofFIG. 2.

FIG. 4 is a cross-sectional view taken along line 4—4 of FIG. 2.

FIG. 5 is a cross-sectional view taken along line 5—5 of FIG. 2.

FIG. 5A is an alternative cross-sectional view taken along line 5—5 ofFIG. 2.

FIG. 5B is a side view of the alternative embodiment of FIG. 5A.

FIG. 5C is a side view of another embodiment of FIG. 2.

FIG. 5D is a further alternate cross-sectional view taken along line 5—5of FIG. 2.

FIG. 5E is a still further alternate cross-sectional view taken alongline 5—5 of FIG. 2.

FIG. 6 illustrates an alternative embodiment of the intravascularballoon catheter of the present invention, shown with the tubularcatheter body and first balloon structure separated from one another.

FIG. 7 is a cross-sectional view taken along line 7—7 of FIG. 6

FIG. 8 is a cross-sectional view taken along line 8—8 of FIG. 6.

FIG. 9 is an end view taken along line 9—9 of FIG. 6.

FIG. 10 is a cross-sectional view taken along the line 10—10 of FIG. 6.

FIG. 11 is a cross-sectional view taken along the line 11—11 of FIG. 6.

FIG. 12 is a schematic illustration of introduction of the intravascularballoon catheter of FIG. 1 to a region in the coronary vasculature.

FIG. 13 is a cross-sectional view taken along line 13—13 of FIG. 12.

FIG. 13A shows an alternative cross-sectional view similar to FIG. 13.

FIGS. 14A–14H illustrate the steps in an exemplary method preformedusing the intravascular catheter of FIG. 1 in accordance with theprinciples of the present invention.

FIGS. 15 illustrates a kit in accordance with the principles of thepresent invention.

FIGS. 16A illustrates the intravascular balloon catheter of FIG. 1 witha deployable embolic capture element on the tubular catheter body.

FIGS. 16B illustrates the intravascular balloon catheter of FIG. 1 witha deployable embolic capture element on the first balloon structure.

FIG. 17A illustrates the intravascular balloon catheter of FIG. 1 with asecond balloon on the tubular catheter body.

FIG. 17B illustrates the intravascular balloon catheter of FIG. 1 withan expandable vascular prosthesis.

FIG. 18 illustrates the intravascular balloon catheter of FIG. 1 with anatherectomy element.

FIG. 19 illustrates the intravascular balloon catheter of FIG. 1 with apressure sensor.

FIG. 20 illustrates the intravascular balloon catheter of FIG. 1 with aninfusion port.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

Intravascular balloon catheter 10 constructed in accordance with theprinciples of the present invention is illustrated in FIGS. 1–5. Theintravascular balloon catheter 10 comprises a catheter body 12 and aballoon structure 14. The catheter body 12 is an elongated structurehaving a proximal end 16, a distal end 18, and a guidewire lumen 20(FIG. 5) extending therebetween. The catheter body 12 preferablycomprises a tubular member having at least one lumen. In some instances,the catheter body may comprise multiple tubular members coupled to oneanother to form an elongated structure. A perimeter of the catheter bodymay have a circular shape, as shown in FIG. 5, an oblong shape, as shownin FIG. 5D or an elliptical shape, as shown in FIG. 5E. Optionally, atapered cone 22, atraumatic tip, or other distal structure may beprovided at the distal end 18 in order to facilitate introduction of thecatheter body through the vasculature. Alternatively, the distal end ofthe catheter body may be axially tapered for a length of at least 3 mm.

Tubular catheter body 12 will have dimensions selected to accomodate theparticular target location within the vasculature to be treated. Usuallythe tubular catheter body will have a length in the range from 50 cm to200 cm, typically 125 cm to 150 cm for treatment of the coronaryvasculature. The outer diameter of the tubular catheter body will alsobe chosen depending on the intended use, with catheter bodies typicallyhaving a diameter in the range from 1 French (F; 0.33 mm) to 10 F,typically from 2 F to 5 F. The diameter of the guidewire lumen will beselected to receive a conventional coronary or other guidewire. Suchguidewires typically have diameters of 0.01 inch (0.25 mm) to 0.035 inch(0.9 mm) and the corresponding guidewire lumens will typically havediameters in the range from 0.2 mm to 2 mm, usually from or 0.4 mm to0.6 mm, respectively.

The tubular catheter body may be formed from polymer materials,composite materials, braided materials, or metal materials. Typically,the tubular catheter body is formed from hypotube or as extrusions ofpolymeric resins. Suitable resins materials include polyamides (nylons)polyimides, polyvinylchloride, PBAX, PTFE, and the like. Catheter bodiesmay optionally be reinforced with braids, coils, filaments or othermaterials in order to enhance the pushability and/or reduce the wallthickness. The tapered distal tip 22 may be formed integrally with theremainder of the catheter body 12 or may be formed separately andattached using adhesives, heat fusion, or other techniques. In someinstances, the tip 22 may be formed from a particularly soft material inorder enhance a traumatic introduction of the catheter.

In a first alternative construction, as shown in FIGS. 5A, tubularcatheter body 12 may include an axial slit 24 to removably receive aninflation tube 26 which is attached at the proximal end of the balloonstructure 14. Inclusion of the slit 24 can reduce the overall diameter(profile) of the catheter. As a second alternative, the guidewire lumen20 can have an axial slit 28, as shown in FIG. 5B, which permitswithdrawal of the guidewire from the lumen 20 as the catheter iswithdrawn from the patient. In place of slit 28, the tubular catheterbody 12 could be provided with a frangible “break way” structure topermit opening of the lumen as the catheter is withdrawn and theguidewire removed. Alternatively, the catheter body 12 may include aspiral slit 25 over at least a portion of the length of the guidewirelumen, as depicted in FIG. 5C.

The balloon structure 14 comprises the inflation tube 26 having aninflation lumen 29 (FIG. 3) extending axially therethrough. A Luer orother connector 30 is attached to a proximal end 32 of the inflationtube 26, and a balloon assembly 34 is attached at the distal end 36. Theinflation tube has a length in the range from 10 cm to 150 cm. As analternative, an axial groove 102 may be formed over at least a portionof the length of the inflation tube 26 to removably receive the catheterbody 12, as shown in FIG. 3A. The groove has a length in the range from10 cm to 150 cm, an opening 104 in the range from 0.001 inches to 0.014inches, and an inner diameter in the range of about 0.0145 inches to0.03 inches, preferably from about 0.016 inches to 0.02 inches. Inparticular, the axial groove of the inflation tube facilitates theintroduction and withdrawal of the catheter body 12. The balloonstructure 14 further comprises an inner sleeve 38 and an inflatableballoon 40 attached over an outer surface of the inner sleeve. The innersleeve has a central passage 41 having a diameter which is large enoughto be introduced over the catheter body, usually being from 0.4 mm to 4mm, more usually from 0.8 mm to 2 mm. The inner sleeve 38 is usually asingle lumen tube, but in other embodiments could be a multiple lumentube where only one of the lumens is intended to receive the tubularcatheter body 12. Other lumens could be provided for perfusion or otherpurposes.

The balloon 40 is initially folded over the inner sleeve 38, as shown infull line in both FIGS. 1 and 2. The balloon may be inflated byintroduction of a suitable inflation medium through the inflation tube14 to produce an inflated configuration, as shown in broken line inFIG. 1. The dimensions, materials, and other characteristics of theballoon 40 maybe as generally described in the patent and medicalliterature for angioplasty balloons.

Alternatively, the balloon 40 may be configured for purposes other thanor in addition to angioplasty. For example, the balloon 40 may beconfigured to receive a stent or other balloon expandable vascularprosthesis thereover. Such vascular prostheses include both stents andgraft structures, usually intended to maintain patency of a blood vesselfollowing angioplasty. The stents which may be delivered using theballoon structures of the present inventions will usually be of themalleable or deformable type, where the stent is initially in a narrowdimension to facilitate intraluminal delivery. After placement at thetarget site, the stent or graft is then expanded in situ by internalinflation of the balloon 40, causing expansion of the stent or graftstructure in order to maintain radial expansion after the balloon isremoved. Such balloon expandable stents and grafts are well-described inthe patent and medical literature. See, for example, U.S. Pat. Nos.4,733,665; 4,776,377; 4,877,030; 5,019,090; 5,102,417; 5,123,917;5,195,984; 5,219,355; 5,344,426; 5,360,443; 5,382,261; 5,733,303; and5,792,018, the full disclosures of which are incorporated herein byreference.

While the present invention will usually employ a conventionalinflatable balloon as part of the balloon structure, it will also bepossible to incorporate other radially expansible devices which aregenerally recognized in the art to be equivalent to inflatable balloonsfor the purpose of performing angioplasty and other intravascularinterventional procedures. Such “balloon equivalents” include expansibleshafts, expansible cages, modified balloons (such as half balloons,balloons with channels, etc.), malecots, and the like. Specificalternative structures are taught in U.S. Pat. Nos. 5,944,691;5,533,968; and 6,048,484, the full disclosures of which are taughtherein by reference.

It will be appreciated that, due to their modular nature, theintravascular balloon catheters 10 of the present invention may includemore than one balloon structure, where the different balloon structuresare often intended for different purposes. In a first particularexample, the intravascular balloon catheters may include a first balloonstructure intended for angioplasty and a second balloon structure 14intended for stent placement. In the later case, the second balloonstructure will usually have the stent preloaded over the balloon.Alternatively, of course it will be possible crimp the stent over theballoon immediately prior to use (i.e. in the hospital rather than atthe point of manufacturing).

Referring to FIGS. 6–11, an alternative intravascular balloon catheter50 constructed in accordance with the principles of the presentinventions will be described. Intravascular balloon catheter 50,comprises a tubular catheter body 52 and a balloon structure 54. Thetubular catheter body 52 has a proximal end 56, a distal end 58, and aguidewire lumen 60 (FIGS. 10 and 11) therethrough. In contrast totubular catheter body 12 of intravascular balloon catheter 10, thetubular catheter body 52 of the second embodiment also includes aballoon inflation lumen 62 extending the entire length from proximal end56 to distal end 58 thereof. To introduce both the guidewire through theguidewire lumen 60 and an inflation medium through the inflation lumen62, a proximal hub 64 is removably attached to the proximal end 56 ofthe tubular catheter body 52. The hub includes both an inflation port 66and a guidewire port 68, typically in the form of a hemostasis valve.The proximal hub 64 will be removable in order to permit introduction ofthe balloon structure 54 there-over. Specific designs for removablecatheter hubs which are able to connect to inflation lumens are providedin U.S. Pat. No. 5,810,869, the full disclosure of which is incorporatedherein by reference. A tapered distal nosecone 70 may optionally bemounted at the distal end 58 of the catheter body 52. The nosecone 70may be similar nosecone 22 described in the earlier embodiment.

The balloon structure 54 comprises a balloon assembly 72 including aninner sleeve 74 having a balloon 76 disposed thereover. Inflation of theballoon 76 is provided through inflation lumen 62 in the tubularcatheter body 52. Inflation lumen 62 terminates in a port 78 (FIG. 11)formed on a proximal surface of the nosecone 70. A connector 80 on theballoon assembly 72 mates with the port 78 when the balloon is properlypositioned at the distal end of the tubular catheter body 52. Aninflation medium introduced through the lumen 62 will reach the balloonin order to inflate the balloon.

The balloon structure 54 further includes a shaft 82 which is attachedto a proximal end of the inner sleeve 74 and which extends proximallythere from. Since the shaft is not needed for inflation, it can have asolid core as shown in FIG. 7. The shaft 82, however, will besufficiently long and will have sufficient column strength in order tointroduce a passage 84 of the balloon structure 54 over the tubularcatheter body 52. The proximal hub 64 can be removed whenever the lumenassembly 72 of the balloon structure 54 is to be introduced over orwithdrawn over the proximal end 56 of the tubular catheter body 52. Atall other times, the proximal hub 64 may be placed over the proximal endof the catheter body in order to provide hemostasis for the guidewire aswell as permit connection of the inflation source (not shown) to theballoon 76.

Referring now to FIGS. 12,13, and 14A–14H, use of the intravascularballoon catheter 10 for performing balloon angioplasty followed by stenttreatment of a coronary artery and a patient P will be described. Aballoon catheter 10 may be introduced to a target site in the coronaryvasculature through a guide catheter GC and over a guidewire GW, asillustrated in FIGS. 12 and 13. The intravasculature balloon catheter 10is introduced in through the guiding catheter GC via hemostatic valveand sheath (not shown) and through the femoral artery A to the coronaryvasculature over the aortic arch AA.

Alternatively, as shown in FIG. 13A, the tubular-catheter body 12 maycomprise an axial slit 24 for removably receiving the inflation tube 14,and the guidewire lumen 20 may be axially slit 28 to permit removaland/or introduction of the guidewire.

As shown in FIG. 14A, the guidewire GW will usually be positioned at thetarget site TS, typically a region of stenosis to be treated by balloonangioplasty. Usually, the balloon catheter 10 and guidewire GW will beintroduced together with the guidewire being periodically extendedforward of the distal end 18 of the catheter until the target site isreached, as shown in FIG. 14B.

Once at the target site, TS the balloon 40 is inflated as shown in FIG.14C, in order to expand the occlusion at the target site TS. After theballoon angioplasty treatment is completed, the balloon 40 will bedeflated, as shown in FIG. 14D, with guidewire GW remaining in place.The balloon structure 14 may then be removed from over the tubularcatheter body 12, as shown in FIG. 14E, again with the guidewire GWremaining in place. A second balloon structure 14′ may then beintroduced over the catheter body 12 by pushing the balloon assembly 34distally using the inflation tube 26 (FIG. 14F). After the balloonassembly 34 is in place, a stent S which is in place over the balloonassembly may be deployed by inflating balloon 40, as shown in FIG. 14G.At all times, the guidewire GW has remained in place, while the balloonstructures 14 and 14′ have been exchanged over the tubular catheter body12.

After the stent S has been properly deployed, balloon 40 may be deflatedand the catheter 10 removed. Removal of catheter 10 may be effectedsimultaneously with removal of the guidewire, i.e. the catheter,including both the tubular catheter body 12 and balloon structure 14′,may be withdrawn simultaneously with the guidewire. Alternatively, theballoon structure 14′ could be removed first, with the guidewire GW andthe tubular catheter body 12 then being withdrawn simultaneously. Asstill a further alternative, the guidewire GW may be left in place bywithdrawing the tubular catheter body 12 over guidewire GW. When theguidewire GW is a short guidewire, it will be advantageous to providemeans in the catheter body for pulling the guidewire from the guidewirelumen as the tubular catheter body is withdrawn. For example, thetubular catheter body could include an axial split in order to permitwithdrawal of the guidewire as the tubular catheter bodies withdrawn.This allows the treating physician to maintain a hold on the guidewireas the tubular catheter body is withdrawn. Alternatively, catheter bodycould have a splitable structure which permits the catheter body to bepeeled part as the catheters withdrawn. Peeling apart catheter alsopermits the treating physician to have access to the guidewire at alltimes of the withdrawal of the catheter body 12. Again, the procedure,the stent S will remain in place within the target site, as illustratedin FIG. 14H.

The system components of the balloon catheters of the present inventionmay be configured as kits as shown in FIG. 15. The kits may comprise anyone or more of the system components together with instructions for useIFU and/or sterile packaging SP. Usually, the kits will comprise atleast a tubular catheter body, e.g. tubular catheter body 12, and oneballoon structure, e.g. balloon structure 14. Optionally, the kit willinclude at least a second balloon structure 14, and the second structuremay carry a balloon expansible or other vascular prosthesis, e.g. anstent S. The IFU may set forth any of the methods described herein.

Referring now to FIG. 16A, an intravascular balloon catheter 10 mayfurther comprise a deployable embolic capture element 90 on the tubularcatheter body 12, typically located within 20 cm of the distal end 18 ofthe catheter body 12. Alternatively, the intravascular balloon catheter10 may comprise a deployable embolic capture element 90′ on the innersleeve 38 of the first balloon structure 14, as depicted in FIG. 16B.The deployable embolic capture element 90, 90′ may comprise coils,wires, braids, mesh, and the like and take on a variety of shapes, i.e.,a funnel shape (FIG. 16A), a parachute shape (FIG. 16B), etc.Preferably, the embolic capture element 90, 90′ is formed from anickel-titanium alloy (such as Nitinol™ alloy), spring stainless steel,or like materials and may additionally be contained or coated with apolymer material. The expandable embolic capture element 90, 90′ allowsfor filtering and/or suctioning of any emboli (which may potentiallyocclude a body lumen) before, during, and/or after treatment with theintravascular balloon catheter 10. The embolic filter 90, 90′ willtypically have micro size holes in the range of about 1 micron to 100microns for the retrieval of emboli, wherein the embolic filter isreleased open and closed, at least in party, by axial or radial movementof the inflatable balloon structure 40 or the catheter body 12.

Referring now to FIGS. 17A and 17B, the intravascular balloon catheters10 of the present invention may further comprise a second expandableballoon 92 on the tubular catheter body 12 distal the first balloonstructure 40. The second balloon 92 will have dimensions,characteristics, and be formed from materials similar to the firstballoon structure 40, as described above. The second balloon 92 itselfmay also carry a balloon expandable vascular prosthesis 94, asillustrated in FIG. 17B. In some instances, the first balloon structure40 may perform angioplasty or other therapeutic or diagnosticprocedures, while the second balloon 92 may be intended to deliver astent 94 after the angioplasty treatment. Thus, such an embodimentadvantageously allows for sequential treatments in a single catheterstructure. Alternatively, the intravascular balloon catheter of thepresent invention may comprise a self-expanding vascular prosthesis onthe catheter body, typically located within 20 cm of the distal end ofthe catheter body. The vascular prosthesis may be positioned distal tothe first balloon structure or at least partially under the firstballoon structure in the unexpanded state. The self-expanding prosthesismay be formed from steel, nickel titanium, shape memory alloy, cobalt,composite material, and the like. Typically, the self-expandingprosthesis will be deployed, at least in part, by axial or radialmovement of the first balloon structure or the catheter body.

Referring now to FIG. 18, the intravascular balloon catheters 10 of thepresent invention may further comprise an atherectomy element 96 coupledto the distal end 18 of the tubular catheter body 12. Those skilled inthe art will recognize that the atherectomy element may comprise a bladeelement, a malecot, coils, wires, braids, mesh, and any other structuresuitable for occlusion removal in a body lumen. FIG. 19 illustrates thatthe intravascular balloon catheters 10 of the present invention mayfurther comprise a pressure sensor 98 coupled to the distal end 18 ofthe tubular catheter body 12. The pressure sensor 98 may comprise apiezoelectric crystal, a resistive device, or the like and willtypically monitor a pressure across a stenosed blood vessel. FIG. 20illustrates that the intravascular balloon catheters 10 of the presentinvention may further comprise at least one infusion port 100 at thedistal end 18 of the catheter body 12. The infusion ports 100 willtypically be in fluid communication with an infusion/guidewire lumen(not shown) in the catheter body. The infusion ports allow fortherapeutic drugs to be directly infused into a treatment site.

Although the foregoing invention has been described in some detail byway of illustration and example, for purposes of clarity ofunderstanding, it will be obvious that certain changes and modificationsmay be practiced within the scope of the appended claims.

1. An intravascular balloon catheter comprising: a catheter body havinga proximal end, a distal end, a guidewire lumen, and an axial slit alongat least a portion thereof; and a first balloon structure comprising aballoon and a passage slidably receivable over the catheter body and aninflation tube removably receivable in the axial slit.
 2. Anintravascular balloon catheter as in claim 1, wherein a perimeter of thecatheter body has a circular shape.
 3. An intravascular balloon catheteras in claim 1, wherein the distal end of the catheter body is axiallytapered for a length of at least 3 mm.
 4. An intravascular ballooncatheter as in claim 1, further comprising an atraumatic tip at thedistal end of the catheter body.
 5. An intravascular balloon catheter asin claim 1, wherein the catheter body is formed from a polymer material,a composite material, a braided material, or a metal material.
 6. Anintravascular balloon catheter as in claim 1, wherein the catheter bodycomprises multiple tubular members coupled to one another.
 7. Anintravascular balloon catheter as in claim 1, wherein the inflation tubeextends proximally from the balloon when the balloon is disposed nearthe distal end of the catheter body.
 8. An intravascular ballooncatheter as in claim 7, wherein the inflation tube has sufficient columnstrength to advance the balloon structure over the catheter body.
 9. Anintravascular balloon catheter as in claim 7, wherein the inflation tubehas a length in the range from 10 cm to 150 cm.
 10. An intravascularballoon catheter as in claim 1, wherein the catheter body issubstantially free from structure at the proximal end which wouldinterfere with passage of the balloon structure over the proximal end ofthe catheter body.
 11. An intravascular balloon catheter as in claim 1,further comprising an expandable vascular prosthesis disposed over thefirst balloon structure.
 12. An intravascular balloon catheter systemcomprising a balloon catheter as in claim 1, further comprising a secondballoon structure having a passage which is slidably receivable over thecatheter body.
 13. An intravascular balloon catheter system as in claim12, further comprising an expandable vascular prosthesis disposed overthe second balloon structure.
 14. An intravascular balloon catheter asin claim 1, wherein the catheter body is axially slit over at least aportion of the length of the guidewire lumen.
 15. An intravascularballoon catheter as in claim 1, wherein the catheter body has a lengthin the range from 50 cm to 200 cm, and outer diameter in the range from1 F to 10 F, and a guidewire lumen diameter in the range from 0.2 mm to2 mm.
 16. An intravascular balloon catheter as in claim 1, wherein theballoon structure further comprises an inner sleeve having an inflatableballoon disposed over an outer surface of the inner sleeve, wherein thepassage is formed axially in the inner sleeve.
 17. An intravascularballoon catheter as in claim 16, wherein the inner sleeve has a lengthin the range form 3 cm to 50 cm and the inflatable balloon has a lengthin the range from 1 cm to 5 cm.
 18. An intravascular balloon catheter asin claim 16, wherein at least a portion of the inner sleeve is slidablyreceivable over the catheter body.
 19. An intravascular balloon catheteras in claim 1, further comprising a deployable embolic capture elementon the catheter body.
 20. An intravascular balloon catheter as in claim19, wherein the deployable embolic capture element is located within 20cm of the distal end of the catheter body.
 21. An intravascular ballooncatheter as in claim 1, further comprising a deployable embolic captureelement on the first balloon structure.
 22. An intravascular ballooncatheter as in claim 1, further comprising a second balloon on thecatheter body.
 23. An intravascular balloon catheter as in claim 22,further comprising an expandable vascular prostheses disposed over thesecond balloon.
 24. An intravascular balloon catheter as in claim 1,further comprising a self-expanding vascular prosthesis on the catheterbody.
 25. An intravascular balloon catheter as in claim 24, wherein thevascular prosthesis is distal the balloon structure in an unexpandedstate.
 26. An intravascular balloon catheter as in claim 24, wherein thevascular prosthesis is at least partially under the balloon structure inan unexpanded state.
 27. An intravascular balloon catheter as in claim1, further comprising an atherectomy element coupled to the distal endof the catheter body.
 28. An intravascular balloon catheter as in claim1, further comprising at least one pressure sensor coupled to the distalend of the catheter body.
 29. An intravascular balloon catheter as inclaim 1, further comprising at least one infusion port at the distal endof the catheter body.